Catheter stylet



May 24, 1938. F. c. WAPFLER 2,118,631

CATHETER STYLET Filed April 3, 1955 IN VEN 1 OR,

AgORNEY.

Patented May 24, 1938 UNITED STATES PATENT OFFICE 2 Claims.

My present invention relates generally to surgical instruments, and hasparticular reference to catheter stylets.

The insertion of a urethral catheter (usually composed of soft, flexiblerubber or the like) requires the aid of a stylet for imparting a certaindegree of rigidity to the catheter. It has been customary practice toemploy a stylet in the form of a rigid, solid wire; and to facilitateprop- ]0 er insertion of the catheter the end of the wire is usuallycurved, whereby a similar curvature is imparted to the tip of thecatheter.

Good practice prescribes that a urethral catheter have at least twoopenings at its inner end,

so that if one of them should become clogged, the other would still beavailable for draining the bladder. Usually, these openings arelaterally disposed, but in a preferred form of catheter, one of theopenings is at the very tip of the catheter,

arranged along an, oblique plane.

Despite precautions that are regularly taken, the forward end of theusual stylet frequently protrudes itself from one of the catheter eyes,and this is especially likely to happen. with catheters having a forwardopening. Because of the rigid and unyielding character of ordinarystylets, such accidental protrusion is dangerous and oftentimes resultsin injury to the patient.

Itv is a general object of my present invention 0 to provide a stylet,of improved structural character, whereby an unusually desirable degreeof rigidity is imparted tov the catheter, notwithstanding the'fact that,the stylet itself is of readily yieldable character, adapted to yieldinstantaneously when its, tip'encounters an obstacle.

Accordingly, in the event that the tip of the present improved, type ofstylet should accidentally protrude from one of the eyes of thecatheter, the likelihood of injury is reduced, to a minimum because ofthe readiness With which the stylet will yield.

A stylet constructed in accordance with my present invention embodiesnot only the foregoing desirable characteristics, but is, in addition,formed in. such a manner that its tip is of relatively blunt andharmless form. Accordingly, it is unusually safe to employ the presenttype of stylet, even in connection with catheters which have an openingat the extreme front tip thereof.

50 I have found that the apparently paradoxical combination ofyieldability, on the. one hand, and rigidity, on the other hand, iscapable of simultaneous attainment by forming the stylet of a helicallywound strip of spring metal, such as 55 stainless steel. Such a body,when pushed end- (c1. 12s s49) wise, and unimpeded, embodies aremarkable degree of rigidity. At the same time, it is readily flexibleso that it adjusts itself readily to curvatures in the urethra. What isof most importance is the fact that when it encounters an un- 5 yieldingobstacle, it buckles with readiness and manifests an unusually great anddesirable yieldability.

One of the features of my invention lies in providing a stylet of thishelically wound type, with 10 the ends of the resultant helix plugged bymeans of a rounded and relatively harmless tip. At least one end portionof the stylet is permanently set into a predetermined gentle curvature.

In a preferred embodiment, I have found it ad- 15 visable to employ aflexible, resilient, stiffening wire which extends longitudinallythrough the helix, and which imparts a desirable additional stiffnesswithout detracting from the yieldable characteristics of the helicallywound strip.

I achieve the foregoing objects, and such other objects as mayhereinafter appear or be pointed out, in the manner illustrativelyexemplified in the accompanying drawing, wherein- Figure 1 is a planview of the forward portion of a typical urethral catheter;

Figure 2 is a view of a stylet constructed in accordance with thepresent invention;

Figure 3 is a view similar to Figure 2, illustrating a modification;

Figure 4 is a view similar to Figure 2, illustrating a furthermodification;

Figure 5 is an enlarged cross-sectional view taken substantially alongthe line 55 of Figure 3;

Figure 6 is an enlarged cross-sectional view taken substantially alongthe line 66 of Figure 4;

Figure 7 is an enlarged fragmentary cross-sectional view showing thepossible employment of a stiffening wire; and

Figure 8 is a perspective view of the catheter of Figure 1 rigidified bymeans of the stylet of Figure 2.

The catheter I0 is of well known character, being approximately fifteeninches in length and being composed of soft rubber approximatelyonesixteenth of an inch thick. The external diameter of the catheter I0is about one-fourth of an inch. At its forward end, the rubber mergesinto a gradual rounded tip I I, and I have illustratively shown two eyesor openings I2 disposed behind the tip and on opposite surfaces. It willbe understood that, in some catheters, one of these openings is disposedalong an oblique plane practically intersecting the tip of the catheter.

he catheter of Figure 1 has practically no rigidity at all, and itsinsertion into the urethra is accomplished with the aid of a stylet ofthe present character. One form is illustrated in Figure 2. The body ofthe stylet is composed of a long strip of spring metal, such asstainless steel, helically wound to form a body it. This body has anexternal diameter of about threethirty-seconds of an inch, and the stripof which the helix is formed is less than one-thirty-second of an inchwide and less than one-sixty-fourth inch in thickness.

My invention is obviously not restricted to any specific dimensions, andthe foregoing figures are stated merely for the purpose of explainingthe general nature of the present construction.

At its opposite ends, the helix is plugged by a rounded tip M which isshown most clearly in Figure 5. It consists of a solid body of metal orthe like, having a rearward attenuated stem l5, which projects into theend of the helix and is maintained in this position by solder or by anyother similar means. The external diameter of each tip H5 issubstantially equal to the external diameter of the body of the stylet.

In Figure 2, the end portion of the stylet has been permanently set intoa predetermined gentle curvature it which has a radius of approximatelythree-eighths inch. This particular curvature is shown merely by way ofexample, and the stylet illustrated in Figure 3 has its end portion setinto the more gradual curvature H which r may, for example, have aradius of approximately two inches. The degree of curvature is optional,and stylets constructed in accordance with the present invention mayhave any predetermined gentle curvature imparted to the end portion,depending upon requirements. This permanent set may be produced inaccordance with any recognized method of tempering spring metal, and itwill be understood that the word permament, as used in this connectionin the present specification and claims, is intended to signify merelythat the normal disposition of the stylet lies along the curvatureimparted thereto. This curved portion of the stylet neverthelessembodies the same yieldability and resilience as the uncurved portionthereof. For example, any of the stylets illustrated will straighten outquite readily and exert merely a mild constant tendency to return, whenreleased, to the curvature into which they have been permanently set.

In Figure 4, I have illustrated on a somewhat smaller scale a modifiedconstruction in which the mid-portion it of the stylet is composed of atruly rigid, rod-like element, preferably tubular in character, as shownmost clearly in Figure 6. A flexible, resilient portion i9 is mounted atone end of the element it in alignment therewith and consists of ahelically wound strip of spring metal, as hereinbefore described. Asimilar flexible, resilient portion 26 is mounted at the opposite end ofthe element l8. At the free end of each of the helical portions a plug14 is mounted in the manner most clearly shown in Figure 5.

Each of the helixes may be secured to the rodlike portion H3 in anydesired manner, preferably by providing attenuated portions 2! on theelement I8 over which the helix ends are disposed, and secured inposition by means of solder or the like. It will be observed that theexternal diameter of the portion i8 is thus substantially equal to theexternal diameter of the helically wound portions.

The advantage of the construction of Figure 4 lies in the fact that theexpense of Winding the helix for the full length of the stylet is saved,the midportion not requiring the degree of yieldability which the endportions should have in order for the stylet to be safely used. In theembodiment of Figure 4, I have shown the portion I9 permanently set intoa gentle curvature similar to that of Figure 3, and I have shown theopposite end portion substantially straight. Any suitable curvatures maybe provided, and they are preferably different in degree, so that theoperator using the device of Figure 4 may have at his immediate disposala stylet which is virtually equivalent to two different stylets ofdifferent curvatures, depending upon which end he inserts into thecatheter.

In any of the embodiments herein illustrated, it may be desirable toinsert an additional stiffening wire of the character illustrated at 22in Figure '7. This wire is of flexible, resilient material; it extendslongitudinally through the helix; and its ends are preferably secured tothe rounded plugs at the ends of the helix. To accomplish this, it ispreferable to construct each of the plugs 23 (see Figure '7) with alongitudinal bore 24 into which the end of the stiffening wire 22projects. It is held in this position by means of solder or the like.

Where the helix has been given a predetermined curvature, thestififening wire 22 is given a similar and corresponding curvature.Where the stylet is constructed with a rigid portion, as

in Figures 4 and 6, the wire 22 extends preferably through the rigidportion, and it is for this reason that this rigid portion is preferablytubular in nature.

Any selected stylet may be employed with any selected catheter, and inFigure 8 I have illustrated, by way of example, the manner in which thestylet of Figure 2 serves to reinforce the catheter of Figure l topermit its insertion into the urethra. It will be observed that thecatheter tip does not conform completely to the natural curvature of theportion I6. This is of no moment, because, presumably, the curvatureimparted to the tip of the catheter by the stylet of Figure 2 is thedegree of bending which the operator desires to have. degree ofangularity, he would employ a stylet having a more gradual curvature.

The reinforced catheter embodies just the proper degree of rigiditywhich is necessary to facilitate its insertion. It is not too stiff orrigid, as is frequently the case with ordinary stylets, nor is it tooyielding to permit proper manipulation. Of primary importance is thesafe character of the present stylet. Should its tip by accident projectfrom one of the eyes of the catheter, no injury is likely to occur,firstly, because the tip is blunted, and, secondly, because the styletembodies a yieldability which causes it to give immediately when pressedagainst an obstruction. This readiness to yield and to bend at isolatedpoints is inherent in the helical structure and is one of thecharacterizing features of the present stylet. The stylet as a whole, atthe same time, embodies the requisite amount of rigidity for the primarypurpose of facilitating insertion of the catheter.

In general, it will be understood that changes in the details, hereindescribed and illustrated for the purpose of explaining the nature of myin- Should he desire a lesser vention, may be made by those skilled inthe art without departing from the spirit and scope of the invention asexpressed in the appended claims. It is, therefore, intended that thesedetails be interpreted as illustrative, and not in a. limiting sense.

Having thus described my invention, and illustrated its use, what Iclaim as new and desire to secure by Letters Patent is-- 1. A catheterstylet comprising a rigid, tubular portion, a pair of flexible,resilient portions mounted at opposite ends thereof in alignmenttherewith, each of said flexible portions comprising a helically woundstrip of spring metal, a rounded tip plugging the free end of eachhelix, and a flexible, resilient, stifiening wire extendinglongitudinally through said rigid and flexible portions and having itsends secured to said tips.

2. A catheter stylet comprising a rigid, tubular portion, a pair offlexible, resilient portions mounted at opposite ends thereof inalignment therewith, each of said flexible portions comprising ahelically wound strip of spring metal, a rounded tip plugging the freeend of each helix, the end portion of one of said helixes beingpermanently set into a predetermined gentle curvature, and a flexible,resilient, stiffening wire extending longitudinally through said rigidand flexible portions, said wire having a permanent set conforming tosaid curvature and having its ends secured to said tips.

FREDERICK CHARLES WAPPLER.

